1. Technical Field
The present invention relates, generally, to electrical component interconnection analysis, and more particularly, to a method of providing global or comprehensive analysis into the mechanical and electrical integrity of all interfaces in an electronic component interconnection scheme. More particularly still, the present invention relates to a method of conducting failure analysis using dye penetration in assessing the solder joint assemblies on components, packages, and circuit boards in board packaging assemblies and other high density packaging approaches.
2. Description of the Related Art
Most integrated circuit components that are attached to a circuit board or the like, typically are attached using mechanical means, such as soldering. When the devices were small, having few leads going from the component to the board, a visual inspection could be made to determine whether the bonding had been adequate and whether a good mechanical connection had been obtained with proper solder flow. Currently, the use of Land Grid Array (LGA) wiring/pad designs for silicon chip interconnection, along with Ball Grid Array (BGA) and Column Grid Array (CGA) type modules are used for silicon chip attachment or first level package attachment to a second level board electronic packaging assembly, These schemes are used because of the high density packaging necessity. These packaging designs offer increased wire density over peripheral component attachment schemes that incorporate the use of wire bonded ICs or solder J-lead and gull wing leaded modules.
Unfortunately, the solder joints that are made on LGA-type packaging designs cannot be visually inspected beneath chip or component bodies after carrier attachment. Accordingly, strict assembly process controls must be placed on variables that affect successful and reliable solder joint formation on both component and carrier.
At present, available techniques that provide for inspection of LGA interconnections are quite costly and do not provide the required visual clarity in all cases or are time consuming and yield information on a limited number of solder joints. For example, X-ray laminography is expensive and time consuming and does not provide a visual account of the scanned unit. Additionally, metallographic cross sectioning, or the slicing of a unit, to view the solder joint in a side view only shows the exposed joint, without showing whether any other portion that is unexposed.
Accordingly, what is needed is an inspection method that provides for a comprehensive analysis of all LGA-type interconnections and all associated LGA interconnection interfaces that provides a useful understanding of critical variables involved in assembly process development, process qualification, and a production ramp, and which can prompt the occurrence of otherwise unnecessary rework or potential for latent field defects in shipped products.